disable parallel build

Author: MariusCausemann

setup.py

@@ -53,7 +53,7 @@ def build_extension(self, ext):
             cmake_args += [
                 '-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_{}={}'.format(cfg.upper(), extdir)]
         else:
-            build_args += ['--', '-j2']
+            build_args += ['--', '-j1']
 
         env = os.environ.copy()
         env['CXXFLAGS'] = '{} -DVERSION_INFO=\\"{}\\"'.format(